It is to be appreciated that any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the present disclosure. Further, the discussion throughout this specification comes about due to the realisation of the inventor and/or the identification of certain related art problems by the inventor. Moreover, any discussion of material such as documents, devices, acts or knowledge in this specification is included to explain the context of the disclosure in terms of the inventor's knowledge and experience and, accordingly, any such discussion should not be taken as an admission that any of the material forms part of the prior art base or the common general knowledge in the relevant art in Australia, or elsewhere, on or before the priority date of the disclosure and claims herein.
Doors normally require a latch mechanism so that they can be secured in the closed position. Interior doors tend to have a simple latch, the main body of which is located adjacent to the closing edge of the door. The latch can be manually operated by a handle, such as a lever or knob that turns, moving an internal latch mechanism. As the handle is moved, a latch hook engages/disengages with a plate that is attached to the door jamb or door frame, thus securing/releasing the door.
Sliding door locks often do not include protruding handles such as levers or knobs, for aesthetic or practical reasons. In particular, protruding handles are not suitable for use with cavity sliding doors, that is, door panels which are typically hidden from view by sliding them into a wall cavity. Protruding handles would stop the door from being entirely slid into the cavity, or particularly large wall cavities would be required.
Protruding door handles are therefore often replaced by a pair of recessed cups mounted on either side of the door panel, one of the cups housing an actuation lever and the other typically including an emergency release device. The lever is manually rotated to extend or retract a bolt from the face plate. A strike plate is mounted on the door frame opposite the closing edge of the door and includes an opening complimentary to the bolt. When the door is closed, the bolt can be extended from the latch body, which in turn causes the hook to extend from the bolt and engage the strike plate to retain the door in the closed position. To open the door, the hook disengages from the strike plate and retracts into the bolt, and the bolt in turn retracts into the latch body.
Sliding door locks generally include a lock bolt of generally rectangular cross section with a longitudinal axis parallel to the side edges of the door and a transverse axis normal to the bottom and top edges of the door.
For example Australian patent 782549 (Gainsborough Hardware Industries Ltd), U.S. Pat. Nos. 5,452,928, 5,529,351 and 5,816,629 disclose cavity sliding door locks in which the hook extends from and retracts into, the bolt.